Jacobs (Canada)

Purpose The purpose of this paper is to investigate the mechanisms controlling the bond formation among extruded polymer filaments in the fused deposition modeling (FDM) process. The bonding phenomenon is thermally driven and ultimately determines the integrity and mechanical properties of the resultant prototypes. Design/methodology/approach The bond quality was assessed through measuring and analyzing changes in the mesostructure and the degree of healing achieved at the interfaces between the adjoining polymer filaments. Experimental measurements of the temperature profiles were carried out for specimens produced under different processing conditions, and the effects on mesostructures and mechanical properties were observed. Parallel to the experimental work, predictions of the degree of bonding achieved during the filament deposition process were made based on the thermal analysis of extruded polymer filaments. Findings Experimental results showed that the fabrication strategy, the envelope temperature and variations in the convection coefficient had strong effects on the cooling temperature profile, as well as on the mesostructure and overall quality of the bond strength between filaments. The sintering phenomenon was found to have a significant effect on bond formation, but only for the very short duration when the filament's temperature was above the critical sintering temperature. Otherwise, creep deformation was found to dominate changes in the mesostructure. Originality/value This study provides valuable information about the effect of deposition strategies and processing conditions on the mesostructure and local mechanical properties within FDM prototypes. It also brings a better understanding of phenomena controlling the integrity of FDM products. Such knowledge is essential for manufacturing functional parts and diversifying the range of application of this process. The findings are particularly relevant to work conducted on modeling of the process and for the formulation of materials new to the FDM process.

In light of the recent success of artificial intelligence (AI) in computer vision applications, many researchers and physicians expect that AI would be able to assist in many tasks in digital pathology. Although opportunities are both manifest and tangible, there are clearly many challenges that need to be overcome in order to exploit the AI potentials in computational pathology. In this paper, we strive to provide a realistic account of all challenges and opportunities of adopting AI algorithms in digital pathology from both engineering and pathology perspectives.

With the emergence of digital pathology, searching for similar images in large archives has gained considerable attention. Image retrieval can provide pathologists with unprecedented access to the evidence embodied in already diagnosed and treated cases from the past. This paper proposes a search engine specialized for digital pathology, called Yottixel, a portmanteau for "one yotta pixel," alluding to the big-data nature of histopathology images. The most impressive characteristic of Yottixel is its ability to represent whole slide images (WSIs) in a compact manner. Yottixel can perform millions of searches in real-time with a high search accuracy and low storage profile. Yottixel uses an intelligent indexing algorithm capable of representing WSIs with a mosaic of patches which are then converted into barcodes, called "Bunch of Barcodes" (BoB), the most prominent performance enabler of Yottixel. The performance of the prototype platform is qualitatively tested using 300 WSIs from the University of Pittsburgh Medical Center (UPMC) and 2,020 WSIs from The Cancer Genome Atlas Program (TCGA) provided by the National Cancer Institute. Both datasets amount to more than 4,000,000 patches of 1000 × 1000 pixels. We report three sets of experiments that show that Yottixel can accurately retrieve organs and malignancies, and its semantic ordering shows good agreement with the subjective evaluation of human observers.

A comprehensive knowledge of the available grounding strategies and their effects is essential for design, operation, and protection of the dc microgrid. This paper investigates and compares different dc microgrid grounding strategies that involve the choice of grounding configurations and grounding devices. The impacts of different grounding strategies on line-to-ground (LG) fault detection and protection, transient LG fault current magnitude, leakage current level, common mode voltage, personnel/equipment safety, system reliability, service continuity, and insulation requirements are thoroughly investigated. LG fault response of a low-voltage dc microgrid with different grounding devices is studied by detailed simulation of a realistic study system modeled in the PSCAD software. The study results indicate that: 1) the ungrounded, bipolar solidly grounded, unipolar parallel resistance grounded, and bipolar resistance grounded dc microgrids enable LG fault ride through, due to the low fault current; 2) the unipolar solidly grounded, bipolar solidly grounded, diode-grounded, and thyristor-grounded dc microgrids experience significantly large transient discharge currents under LG faults; and 3) the unipolar solidly grounded, diode-grounded, thyristor-grounded, and unipolar low-resistance-grounded dc microgrids provide considerable steady-state LG fault current which necessitates fast detection and clearance of faults.

Modern vehicles, including autonomous vehicles and connected vehicles, have adopted an increasing variety of functionalities through connections and communications with other vehicles, smart devices, and infrastructures. However, the growing connectivity of the Internet of Vehicles (IoV) also increases the vulnerabilities to network attacks. To protect IoV systems against cyber threats, Intrusion Detection Systems (IDSs) that can identify malicious cyber-attacks have been developed using Machine Learning (ML) approaches. To accurately detect various types of attacks in IoV networks, we propose a novel ensemble IDS framework named Leader Class and Confidence Decision Ensemble (LCCDE). It is constructed by determining the best-performing ML model among three advanced ML algorithms (XGBoost, LightGBM, and CatBoost) for every class or type of attack. The class leader models with their prediction confidence values are then utilized to make accurate decisions regarding the detection of various types of cyber-attacks. Experiments on two public IoV security datasets (Car-Hacking and CICIDS2017 datasets) demonstrate the effectiveness of the proposed LCCDE for intrusion detection on both intra-vehicle and external networks.

In recent years, computer vision techniques have made large advances in image recognition and been applied to aid radiological diagnosis. Computational pathology aims to develop similar tools for aiding pathologists in diagnosing digitized histopathological slides, which would improve diagnostic accuracy and productivity amidst increasing workloads. However, there is a lack of publicly-available databases of (1) localized patch-level images annotated with (2) a large range of Histological Tissue Type (HTT). As a result, computational pathology research is constrained to diagnosing specific diseases or classifying tissues from specific organs, and cannot be readily generalized to handle unexpected diseases and organs. In this paper, we propose a new digital pathology database, the ``Atlas of Digital Pathology'' (or ADP), which comprises of 17,668 patch images extracted from 100 slides annotated with up to 57 hierarchical HTTs. Our data is generalized to different tissue types across different organs and aims to provide training data for supervised multi-label learning of patch-level HTT in a digitized whole slide image. We demonstrate the quality of our image labels through pathologist consultation and by training three state-of-the-art neural networks on tissue type classification. Quantitative results support the visually consistency of our data and we demonstrate a tissue type-based visual attention aid as a sample tool that could be developed from our database.

Grounding strategy of an ac microgrid affects its line-to-ground fault response, personnel/equipment safety, service continuity, insulation requirements, and protection criteria. Therefore, a comprehensive knowledge of the available grounding strategies and their effects is essential for design and operation of the microgrid components and especially its protection. In this paper, characteristics of different ac distribution system grounding devices and grounding configurations are investigated. Subsequently, ac microgrid grounding requirements and issues are identified based on the unique characteristics and constraints of microgrids. The results of the aforementioned investigations are used to identify the best grounding strategies, i.e., grounding configurations, transformer connection types, and grounding devices, for the ac microgrid. The study results indicate that the four-wire multigrounded configuration is the most suitable choice for the majority of microgrids, especially in North America. The Yg/Δ and Yg/Yg transformers are identified as the most appropriate choices for distributed energy resources (DER) interface to the four-wire multigrounded microgrid. Besides, low-reactance and low-resistance grounding devices are recommended for the DER interface transformers.

OBJECTIVE: Neurosurgical resources are concentrated in tertiary referral centers, whereas emergencies identified from district general hospitals are traditionally referred by telephone consultation (TC). Recent advances in communication technology offer the alternative options of teleradiology (TR) and video consultation (VC). This study aimed to determine the differences among these three consultation methods on the basis of their process-of-care indicators, clinical outcomes, and cost-effectiveness. METHODS: Patients with emergency neurosurgical conditions (head injury, stroke, and miscellaneous) from a district general hospital were randomized to three different modes of consultation: TC, TR, or VC. Process-of-care indicators (postresuscitation Glasgow Coma Scale score, consultation time required, diagnostic accuracy, and transfer decision and safety), 6-month clinical outcome, and cost-effectiveness of the three consultation modes were correlated. RESULTS: In a 3-year period, 710 patients were recruited and randomized to the three consultation modes (n = 235, 239, and 236, respectively). Demographic and clinical data were comparable. TR and VC showed a definite advantage in diagnostic accuracy over TC (89.1 and 87.7% versus 63.8%; P < 0.001). However, duration of the corresponding consultation process was longer for TR and VC than TC (1.01 and 1.3 h versus 0.70 h). A high failure rate (30%) was noted in VC. Thirty-three percent of patients were transferred to the neurosurgical center after consultation. The difference in consultation modes did not have an impact on transfer rate and safety. There was a trend toward more favorable outcome (61%; P = 0.12) and a reduced mortality (25%; P = 0.025) in TR compared with TC (54 and 34%, respectively) and VC (54 and 33%, respectively). The mean cost per patient in the VC group was slightly higher than the other two groups (TC versus TR versus VC = 14,000 US dollars versus 14,400 US dollars versus 16,300 US dollars, respectively), but the differences were not statistically significant. CONCLUSION: Emergency neurosurgical consultation assisted by TR and VC achieved a higher diagnostic accuracy in comparison with conventional TC. Although VC did not show an advantage over TR in process-of-care indicators, clinical outcome, and cost, it has been proven to be a safe mode of consultation in emergency neurosurgery.

PURPOSE: The purpose of this study was to investigate the effect of acute ingestion of modafinil (M) on time to exhaustion during high-intensity exercise. Modafinil (M) is a psychostimulant developed to treat narcolepsy, with "arousal" properties attributed to an increased release of dopamine in the CNS. Because other stimulants with similar properties have ergogenic effects, it was hypothesized that acute treatment with M would enhance physical performance. METHODS: Fifteen healthy male subjects, with a maximal aerobic power (VO2max) of 47 +/- SD 8 mL x kg x min, exercised on a cycle ergometer for 5 min at 50% VO2max and then at approximately 85% VO2max to exhaustion. They did this weekly for 3 wk: a control trial (C) the first week, and then 3 h after ingesting either placebo (P) or M (4 mg x kg) during the remaining 2 wk. The P and M trials were conducted with a balanced order, double-blind design. RESULTS: : Mean +/- SD times to exhaustion at 85% VO2max (TE) were 14.3 +/- 2.8, 15.6 +/- 3.8 and 18.3 +/- 3.5 min for the C, P, and M trials, respectively. TE for M was significantly longer than for the C and P trials. Oxygen uptake at exhaustion was slightly but significantly greater for M compared with P and C. HR increased with time and was further elevated by M. Subjective ratings of perceived exertion (RPE) were significantly lower for M compared with C and P but only after 10 min of exercise at 85% VO2max. CONCLUSION: Acute ingestion of modafinil prolonged exercise time to exhaustion at 85% VO2max and reduced RPE. The RPE results suggest that the dampening of the sensation of fatigue was likely a factor responsible for the enhanced performance.

Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverable. For the first time, comprehensive mapping and tracking the fate of cellulose across various unit processes at full-scale in two water resource recovery facilities located in North America and Europe was undertaken. The influent cellulose content accounted for approximately one-third of the total suspended solids (TSS). Although about 80% of the raw wastewater cellulose was removed in primary treatment, the type of primary treatment process (rotating belt filter [RBF] vs. primary clarification [PC]) had a significant impact on cellulose capture and diversion. The high cellulose content of the RBF sludge accounting for 35% of the TSS facilitates cellulose recovery. For the North American plant, with a conventional activated sludge process (SRT of 6-7 days, preceded by PC), cellulose biodegradation efficiencies of 70%-90% of the PC effluent were observed in summer and winter. For the European plant, with a modified University of Cape Town process (SRT of 14 days, without primary treatment in train 2, or preceded by RBF in train 1), comparable cellulose biodegradation efficiencies were also observed. Results from laboratory SBRs indicated that cellulose biodegradation efficiency at room temperature was 86% of the influent cellulose. PRACTITIONER POINTS: Cellulose fate was tracked across two different WWTPs in two different geographies. Cellulose in the influent wastewater accounted for 1/3 of the total suspended solids. Primary treatments were able to capture more than 80% of the influent cellulose. Cellulose was biodegraded in secondary treatment, resulting an effluent of 2-3 mg/L.

The high demolition rate (∼60%) of reinforced concrete (RC) buildings that generally performed well in Christchurch, New Zealand, has been one of the most important lessons from the Canterbury Earthquakes. In an effort to understand such an outcome, various factors influencing the post‐earthquake decisions on buildings (demolition or repair) are explored, focusing on multi‐story RC buildings in Christchurch Central Business District (CBD). Using empirical data, logistic regression analysis was conducted to explain the likelihood of building demolition. Several explanatory factors were found to be statistically significant: assessed damage, occupancy type, heritage status, number of floors, and construction year. From in‐person interviews conducted in New Zealand, contextual factors such as insurance policy and changes in legislation were also found to play a significant role in the post‐earthquake decisions on buildings.

This paper intends to show some special topics on ground-fault protection. Single-line-to-ground faults are the most common fault type, the protection engineer has to understand how often these occur, the nature, and also the effects of a single-phase arcing fault. System grounding also affects the magnitude of fault current, protective devices selection, and settings. This paper discusses line-to-ground (LG) and associated issues, such as transformer energization and line-charging current. Such considerations shall be addressed when setting grounding relays and to adopt the best LG protection practices.

An electrical distribution architecture has a vital impact on the performance of an installed system throughout its lifecycle. The architecture of an installation involves the configuration, the choice of power sources (utility and alternate power source), the definition of the different distribution levels, and the choice of equipment. Previous papers have introduced a language program for analyzing and transcribing the instructions of the safety procedures for each working zone and of the integrity procedures for each source node versus the loss of service continuity (the Parise program). Each node presents a kit of instructions as a logic gene, describing a complete and reversible evolution of the component switching means from an opening status to a closing one. This paper deals with the architecture of a power system and the combination of procedures in the operation on a nodes system. It will show the impact of the architecture on the comprehensive procedures for a complex system. To enhance the integrity of power system analysis and operation, the design could adopt the cut&tie rule, introducing ring configuration and floating nodes. The suggested advanced approach assists in the elaboration of the procedures for switching from one set or configuration of a power system to another and will help the training of operators in defining the instructions to be used in the development and the operating of each power system.

Time-lapse 3D seismic monitoring was conducted in the Japan Canada Oil Sands Limited (JACOS) Hangingstone steam-assisted-gravity-drainage (SAGD) operation area in Alberta, Canada, to delineate steam-affected areas. The time-lapse surveys, acquired in February 2002 and March 2006, show distinct response changes around the SAGD well pairs. In addition, 3D P-SV converted-wave processing and analysis were applied on the second 3D data set (recorded with three-component digital sensors) for a reservoir characterization study.

The growth of Arctic shipping requires effective tools to assess the appropriateness of existing practices on safety and resilience levels, especially in the enforcement of the Polar Code. Understanding such, in this study, we develop a resilience index using the Fuzzy Analytical Hierarchy Process (FAHP). Data collection for the index’s implementation started during a research voyage along the Northwest Passage in Canada. It resulted in 61 valid responses, upon which the relative importance and the level of satisfaction of resilience builders were investigated. The findings indicate that factors that rank high on importance are, in many cases, not that high on satisfaction. This presents dilemmas regarding the effectiveness of the current practices in promoting safe and resilient Arctic shipping management practices. This study fills an important gap in the monitoring of safety and resilience practices in Arctic shipping. In turn, this affects the future actions and research of researchers, stakeholders, and right-holders in the Arctic area.

The design of a power system has to be comprehensive in regard to the system traditional design configuration aspect as well as its operational safety aspect, such as management and maintenance. The comprehensive design has to survey and define both aspects during the different design phases and during the overall operational life cycle of the system. A new methodology has been suggested to close the gap between the traditional system design integrity studies and their counterpart studies associated with system operational safety aspect

This paper demonstrates practical considerations when studying overcurrent protection coordination in industrial systems and applying related IEEE Standards. This paper is divided into two parts. Part one focuses on protection coordination for high-voltage and medium-voltage industrial systems. Part two covers balance of distribution system topics. The main discussed subjects are time/chronologic, current/amperometric, as well as zone selective interlocking coordination. Other factors that affect coordination are also addressed. Suitable selections of the relay time-current characteristic are presented. This paper also includes practical details for accepted coordination time interval in coordinated systems.

KEY POINTS Menopause is defined as 1 year of amenorrhea caused by declining ovarian reserve or as the onset of vasomotor symptoms in people with iatrogenic amenorrhea. It is preceded by perimenopause or the menopause transition, which can last for as long as 10 years. Although many treatments exist

In electrical installations, each working zone and each source node present a kit of operating instructions as a logic gene. Previous papers have introduced a new approach and a language of a ternary code for operational procedures (Parise program). This paper deals with some comments on definitions and the syntax of the operational language. The same status of switching defines working zones or nodes by double operating value, free value, and packed value, thereby discriminating between decision and execution, and executed act from verification. The recommended command is a double click. The instructions have to be assembled like in a genetic cryptogram in the context of an electrical power system and of its architecture and constitution. They describe the complete and reversible evolution of the operational procedures for safe transition from a one set of switching configuration to another ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">waves of safe sets</i> ). Transitions maps are introduced to assist in the elaboration of operational procedures and to help the training of operators, their competence, and performance. These maps are specialized for the operational procedures more than the Karnaugh maps of digital electronics. On the basis of the logic gates, the basic equivalent mechanical connectives are defined to guide the operational procedures. A switching simulator based on electronic gates can be very useful for verifying the effects of any set of switching operations, adopting for commands the double click.

Abstract Ore blending is a strategy developed in the oil sands industry to enhance bitumen recovery from low grade oil sands ores. It involves blending low grade ores with high grade ores at a certain ratio, resulting in a higher overall bitumen recovery from the mixture than the simple recovery summation of the two extracted separately. To understand the underlying mechanisms, both bitumen‐coated glass beads (−150 + 125 µm) and raw coal particles (−500 + 300, −300 + 150 and −150 µm) were used as carrier materials in this study to simulate bitumen droplets from high grade ores. Experimental results revealed that coal particles were more efficient than hydrophobised bitumen‐coated glass beads in accelerating bitumen recovery and that better bitumen extraction performance was obtained by using smaller sizes of coal. This was attributed to the gravitational effect of larger, heavier particles on the detachment of bitumen‐particle aggregates from bubbles. For smaller sizes of coal (−150 µm), a faster bitumen flotation recovery was achieved with more coal added. An increase in bitumen recovery up to 20–30% (absolute) was obtained by adding coal into the oil sands slurry. The interaction of bitumen with coal particles or bitumen‐coated glass beads during oil sands slurry conditioning and flotation was visually verified from simple coagulation tests. The similarity of ore blending in oil sands extraction to carrier flotation in minerals flotation and the potential application of carrier flotation principles to oil sands extraction were discussed.